This invention relates generally to printer devices. More particularly, the invention pertains to a multichannel system and a method for simultaneously detecting malfunctioning nozzles in a plurality of print heads of a large format printer device to thereby reduce the amount of time required to test whether the nozzles are operating properly.
It is known to produce copies of files on a print media from a host device, e.g., a computer, a facsimile machine, a photocopier, etc., using a printer device. Among the known methods for printing text and the like onto a print medium, it is known to build an image on the print medium by spraying droplets of ink from nozzles provided on print heads of a printer.
As seen in FIG. 1, there is schematically illustrated a part of a known printer device (e.g., a large format printing device) having an array of print heads 100 in a parallel row. More specifically, FIG. 1 illustrates six print heads 102-112. Each of the print heads 102-112 includes a plurality of printer nozzles 202-200n, arranged in two rows, (see FIG. 2) for firing ink onto a print medium 120. Although FIG. 1 depicts the printer device as having six print heads 102-112, printer devices have been known to possess any number of print heads, e.g., two, four, or more. Additionally, although FIG. 2 depicts the print heads 102-112 as possessing two rows of nozzles 202-202n, print heads have been known to possess any number of nozzle rows, e.g., one, two, or more.
Referring back to FIG. 1, in a conventional printer device, the print heads 102-112 are constrained to move in a direction 170 with respect to the print medium 120, e.g., a sheet of paper. In addition, the print medium 120 is also constrained to move in a further direction 160. During a normal print operation, the print heads 102-112 are moved into a first position with respect to the print medium 120 and a plurality of ink droplets are fired from the same plurality of printer nozzles contained within each of the print heads 102-112. After completion of a print operation, the print heads 102-112 are moved in a direction 170 to a second position and another print operation is performed. In a like manner, the print heads 102-112 are repeatedly moved in a direction 170 across the print medium 120 and a print operation is performed after each such movement of the print heads 102-112. When the print heads 102-112 reach an edge of the print medium 120, the print medium is moved a short distance in a direction 160, parallel to a main length of the print medium 120, and another print operation is performed. The print heads 1021112 are then moved in a direction 170 back across the print medium 120 and yet another print operation is performed. In this manner, a complete printed page may be produced.
A more detailed description of the printer device illustrated in FIG. 1 may be found in commonly assigned application Ser. No. 09/502,667, filed on Feb. 11, 2000, by Xavier Bruch et al., (corresponding to Application No. 20020140760, published on Oct. 3, 2002, now U.S. Pat. No. 6,517,183, issued on Feb. 11, 2003), the disclosure of which is hereby incorporated herein by reference in its entirety.
In order to maintain the quality of the printed output of the printer device, it is important to determine whether each of the nozzles provided on each of the print heads 102-112 is functioning properly. In conventional printers, it is known to attempt to detect an ink droplet as it leaves the nozzle between certain print operations. In this respect, a drop detector module 130 is typically used to determine the health (i.e., the proper functioning) of the printer nozzles 200-200n. As seen in FIG. 1, a drop detector module 130 is typically provided outside the region used for printing on to the print medium and generally adjacent to a service station 140 in a conventional printer device.
The service station 140 is generally provided to maintain the health of the print heads 102-112 by providing a means for both cleaning and capping the nozzles 200-200n when the printer device is idle. The service station 140 typically includes a plurality of service station units 142-152 for performing servicing operations on the each of the print heads 102-112. Generally, one service station unit 142-152 is provided for each of the print heads 102-112. The service station units 142-152 are typically housed within a service station frame 154. In use, the service station units 142-152 typically function as reservoirs to collect ink fired or xe2x80x9cspittedxe2x80x9d from a respective one of the print heads 102-112 to thus maintain each of the nozzles 200-200n in a functional state. In addition, each of the service station units 142-152 includes a device for capping the print heads 102-112 when the printer device is idle,
The drop detection module 130 generally operates to detect whether ink is properly fired from each of the nozzles 200-200n of each of the print heads 102-112 by detecting whether a beam of light is broken by an ink droplet. In FIG. 3, there is illustrated schematically a conventional drop detection module 130 used in a printer device. As seen in FIG. 3, the conventional drop detection module 130 generally includes a light emitting diode (LED) 302, a lens 304, a light receiving diode 306, a drop detection unit 308, and an amplifier 312. To detect whether a nozzle is operating properly, a signal is sequentially sent to each nozzle to fire at least one ink droplet. If, in response to the signal, an ink droplet 300 is fired from one of the nozzles (e.g., 202), the ink droplet travels along a path 310. The path 310 traced by the ink droplet 300 is configured to pass between the LED 302 and the light receiving photo diode 306. The light emitted by the LED 302 is collimated by the lens 304 to produce a narrow light beam through which the ink droplet 300 may pass. The lens 304 may be integrally attached to the LED 302 or may constitute a separate element. The photo diode 306 detects the ink droplet 300 by detecting the disturbance in the light beam. In response to the light disruption in the light beam, the photo diode 306 produces a current which is amplified by an amplifier 312 and sent to the drop detection unit 308, The drop detection unit 308 then determines whether the nozzle is operating properly.
The above-described process for determining whether a nozzle is functioning properly is repeated for each of the nozzles 200-200n on each of the print heads 102-112. In order to test each of the nozzles 200-200n, the set of print heads 100 must be accurately positioned over the drop detection module 130. Accordingly, each of the print heads 102-112 must be moved in the direction 170 sequentially over the drop detection module 130. More particularly, each row of nozzles on each of the print heads 102-112 must moved to a position directly over the light beam for an accurate measurement to be obtained. By virtue of the numerous movements required to position each of the nozzles, the potential for misalignment between the nozzle to be tested and the light beam emitted from the LED 302 is relatively large. Additionally, the amount of time required to maneuver each of the rows of nozzles over the light beam for accurate testing thereof is also relatively large. This may be problematic because the time required to test each of the nozzles may sometimes exceed the amount of time allowed for each of the nozzles to be uncapped (e.g., on the order of about one second). Because of this possibility, in certain instances, it may be necessary to maneuver the set of print heads 100 over the service station 140 to thus perform servicing operations on the print heads 102-112 (e.g., xe2x80x9cspitxe2x80x9d ink out of some of the nozzles into respective service station units 142-152) while testing the nozzles, thus further increasing the amount of time required to test each of the nozzles 200-200n. As can be appreciated from the description above, as the number of print heads and hence the number of nozzles increases, the amount time required to test all of the nozzles also increases, thus substantially increasing the time required to print files onto a print medium.
According to specific embodiments and methods, the present invention aims to decrease the amount of time required to test the nozzles of a plurality of print heads in a printer device, to thereby improve the throughput of the printer device as well as to decrease the amount of wasted ink.
According to a preferred embodiment, the present invention pertains to a printer device having a plurality of print heads for printing onto a print medium. Each of the print heads has a plurality of nozzles formed into at least one row. The printer device also includes a service station which has a plurality of service station units for performing servicing operations on the print heads. Additionally, a plurality of modules for detecting malfunctioning nozzles is integrated into respective ones of the service station units or, as a multichannel drop detector, into a service station frame.
According to another aspect, the present invention relates to a print head service station for use in a printer device possessing a plurality of service station units. In addition, the service station includes at least one drop detector module for each row of nozzles of each of the print heads. The drop detector module detects ink droplets fired from a nozzle of a plurality of nozzles in a print head to detect malfunctioning nozzles.
According to yet another aspect, the present invention pertains to a method for testing whether a plurality of nozzles of a plurality of print heads are operating properly. In the method, a plurality of print heads are maneuvered to a position substantially above a service station possessing a plurality of service station units, such that each of the print heads is substantially in a position to have ink droplets fired from each of the nozzles tested by a drop detector module. A signal is sent to each of the print heads to fire an ink droplet from each of the nozzles and a drop detector modules whether an ink droplet was fired by the signaled nozzle.